1. Field of the Invention
This invention relates to a method and apparatus in which the processing performance of a photosensitive material developing is detected, and necessary control is carried out for maintaining the performance within an allowable condition, and an apparatus for practicing the method. More particularly, the invention relates to a method and apparatus for maintaining the developing performance of an automatic developing and printing system which develops a photographic film exposed, and automatically makes a print from the developed film by using a photographic paper.
2. Description of the Related Art
An apparatus is well known in the art in which an exposed photographic film is developed by immersing it in a processing solution, and the film thus developed is automatically subjected to a printing processing to make a print thereof from the film thus developed. An example of the apparatus of this type is disclosed by Published Unexamined Japanese Patent Application No. Sho-64-15741.
The apparatus thus disclosed operates as follows. First, a film cartridge (patrone) accommodating a photographic film which has been exposed but not developed yet, is loaded in the apparatus. Under this condition, the apparatus is started. The apparatus automatically develops the film, and then exposes a photographic paper through the film thus developed. Upon the exposure, the apparatus develops the photographic paper thus exposed, to make a print.
The above-described automatic developing and printing apparatus which develops a photographic film, and make a print from it, has been generally installed at camera stores so as to be effectively used to develop photographic materials to provide prints quickly.
In the above-described automatic developing and printing apparatus including the photographic film developing unit and the printing unit (i.e., a color photographic paper developing unit), the developing performance is controlled separately for the film developing unit and for the photographic paper developing unit so that changes in developing performance are detected and corrected. These changes result from the condensation of the processing solution which is due to the change in temperature of the processing solution or evaporation of the latter, and changes in density of the processing solution which is due to fluctuation in the quantity of supplement solution thereto.
In general, the developing unit and the printing unit are controlled as follows. A photographic film or paper on which control strips (a pattern corresponding to LD, HD, D.sub.max, and D.sub.min) have been formed by exposure and which has not been developed yet, is processed with the developing unit and the printing unit whereas a print is made from an eyeball negative film (a film on which an eyeball-shaped gray pattern has been formed by exposure), thereby to measure the density thereof, so that the conditions of the developing unit and those of printing unit are controlled separately.
Recently, a method has been employed in which an ND filter is built in the light source section of a printing unit, and a densitometer is arranged at the paper discharging outlet thereof, so that operations corresponding to the exposure and print of the eyeball-shaped pattern and the measurement of density thereof are automatically carried out.
Published Examined Japanese Patent Application No. Hei. 3-69094 discloses an example of the processing-performance controlling method, in which the condition of a developing solution is detected by using the control strips thereby to control the amount of supplement solution thereto. On the other hand, Published Unexamined Japanese Patent Application No. Hei. 2-162348 discloses a method in which reference data are provided for each of the factors that adversely affect the processing operation, and the condition of the current processing operation is determined by using the control strips, and the results of determination are compared with the reference data to discover what factor adversely affects the processing operation.
However, a photographic material with the control strips is expensive. Furthermore, in order to prevent the change with time of the photographic material, it is necessary to store the photographic material in a refrigerator. Therefore, it is necessary to restore the temperature of the photographic material to room temperature before it is used. Thus, use of the photographic material with the control strips is rather troublesome, and not economical.
On the other hand, the overall finish of a print depends on the accumulation of errors in both the developing unit and the printing unit. Therefore, it is necessary to control the process to eliminate changes in the overall finish, which are caused by individual errors in the developing or printing unit or by the synergism of those individual changes. This control can be made only by a person skilled in the art.
On the other hand, when, in the apparatus, one condition changes to adversely affect the operation of the apparatus, sometimes the adverse effect may be eliminated by a change in another condition. In this case, correction of the conditions is unnecessary; however, it is difficult to determine that the correction is unnecessary.
Furthermore, the overall finish of a print is determined by the synergetic effect of the performance of the photographic film developing section, the performance of the printing optical system, and the performance of the photographic paper developing section. For instance, a print gradation reproducing characteristic with respect to an object depends on the synergetic effect of photographic film developing contrast performance and photographic paper developing contrast performance. On the other hand, as for a particular object, the printing density depends on the synergetic effect of film developing LD and HD performance, the photometric exposure performance of the printing optical system, and photographic paper developing LD and HD performance. Hence, even if the photographic film developing performance and the photographic paper developing performance are mutually shifted to an extent, the overall finish of the print depends on whether the synergetic effect of them acts to increase the error or whether it acts to decrease it.
Hence, in order to control the photographic film developing performance and the photographic paper developing performance separately, those performances must be controlled excessively strictly for the aimed overall finish. That is, the frequency of maintenance operations, such as replacement of the mother liquor, is increased remarkably. On the other hand, it can be made only by the person skilled in the art whether or not the developing performance is controlled for the aimed overall finish. This is another problem to be solved.